I think the assumption is the turbine will be at 100% power all the time. Charging the ( not existing today but promised in 3 years ) batteries that will provide extra power for take off and climb, and tolerate fairly robust charging in cruise, descent, and taxi. Regenerative charging on descent may be possible, but in reality not used often, depending on traffic control getting adapted to the slow down, passenger comfort in pressure rise, and battery capacity to charge rates without exploding. 3 variables I cannot quantify today. Good luck. A Florida utility is looking to build a giant battery pack to load level an entire grid area to allow intermittent power production. It has to be batteries because there are no mountains to pump water up to a lake & recover the power by gravity. ( as used in New York ) Imho it's a stupid, even insane, use of lithium chemistry batteries, since mass is not an issue, and the chemicals are semi-rare and expensive. Again, imho, Edison iron chemistry cells would be cheaper, not deplete a scarce resource, and will produce Hydrogen gas for co-generation or other purposes. Shipping containers on gravel pads with pallets of Edison cells, covering acres of swampy ( otherwise useless land ) connected with Hydrogen recovery pipes & bus bars, doesn't need light weight cells. It needs sturdy cells that can operate relatively unattended, he easily rebuilt by guys & gals in shirt sleeves with the only hazardous materials being the acid recovered from flushing a cell pallet for rebuilding & acid recovery recycling. I could be wrong on the specifics! But the philosophy of appropriate tech, not using the wrong materials for fad reasons, applies. A giant sports stadium may use carbon fiber for the solar nano film roof, but the seats and roof are on concrete.